They sell these VMs at a higher cost because it requires more expensive components and is limited to host machines with certain configurations. In our experience, it's also harder to request quota increases to get more of these VMs -- some of the public clouds have a limited supply of these specific types of configurations in some regions/zones.
As others have noted, instance storage isn't as dependable. But it can be the most performant way to do IO-intense processing or to power one node of a distributed database.
- https://cloud.google.com/compute/docs/disks/local-ssd
- https://learn.microsoft.com/en-us/azure/virtual-machines/ena...
- https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ssd-inst...
They sell these VMs at a higher cost because it requires more expensive components and is limited to host machines with certain configurations. In our experience, it's also harder to request quota increases to get more of these VMs -- some of the public clouds have a limited supply of these specific types of configurations in some regions/zones.
As others have noted, instance storage isn't as dependable. But it can be the most performant way to do IO-intense processing or to power one node of a distributed database.